Radio signaling system



' i 627,707 May 10 .1927. M. LATOUR RADIO SIGNALING SYSTEM v Filed Auk. 19., 1921 4 Sheets-Sheet 1 avweutoz MANUS LATOUR May'10,1927. 1 I I 1,627,707

M1 LATOUR RADIO SIGNALING SYSTEM Filed 11.19. 1921 4 Sheets-Sheet 2 awwemtoz MARIUS LATOUR May 10 1927-v LATOUR RADIO SIGNALING SYSTEM Filed: Aug. 19. 1921 4 Sheets-Sheet 5 amvwntoz MANUS LATOUR 1,627,707 May 10 1927. M. LATOUR I RADIO SIGNALING SYSTEM Filed Aug.19, 1921 4 Sheets-Sheet 4 Snow/1 :01

MAPJUS LATOUR ia/W Patented May 10, 1927.

MARIUS LATOUR, OF PARIS, FRANCE, ASSIGNOB. TO LATOUR CORPORATION,

JERSEY CITY, NEW JERSEY, A CORPORATION OF DELAWARE.

RADIO SIGNALING SYSTEM.

Application filed August 19, 1921, Serial No. 493,664, and in France August 16, 1915.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. 13., 1313.)

The present invention relates to a contion of continuous waves is well known.-

T his application is based on French Patent No.502,601, filed August 16, 1915; French Patent of Addition No. 22,501, filed August 21, 1915; French Patent of Addition No. 22,650, filed September 27, 1915; French Patent of Addition No. 22,976, filed November 20, 1915; and French Patent of Addition No. 23,178, filed March 8, 1916.

In vacuum tube generators the filament is usually fed by a direct current source. A second direct current source having a relatively high potential (c. g. 500 volts) is provided between the plate and the filament. The plate filament circuit is coupled with the grid filament circuit by means of a transformer, the terminals of which are shunted by a capacity. The continuouswaves produced are communicated to the antennaground circuit either by means of an inductive or conductive coupling.

Such circuit arrangements have two disad vantages:

First, a relatively high potential direct current source must be provided, and second, the receiving circuit must be provided with the well known devices for receiving continuous waves, these devices being more complex than those used for the receiving of dampened waves, no matter whether tickers or the heterodyne principle be used.

My invention is illustrated in the accompanying drawing wherein Figs. 1, 3, 5, 6 and 7 represent various arrangements of apparatus according to the invention, and

Figs. 2 and 4 are curves illustrating the operation of my invention.

The object of the present invention. is to avoid one or both' of these disadvantages.

In accordance with one modification, the continuous wave generator is not fed by a direct current source, but by an alternator having a musical frequency. The circuit arrangement provided for this purpose is shown in Fig. 1. An alternator D is provided in place of a direct current source. It will be seen, therefore, that under these conditions the cathodic generator functions only when the plate has a positive potential, whereby the continuous waves will be generated only during half a period and their intensity will vary as illustrated by the curve of Fig. 2. The receiver provided with a simple crystal detector will receive a musical sound having a tone corresponding to the frequency of the alternator.

Preferably, in this circuit arrangement, the terminals of the alternator are shunted by an assembly. comprising a self induction L and a capacity C. This assembly is tuned to the frequency of the continuous waves and will not offer much resistance to the passage of these waves. The capacity C could be made sufiiciently low to avoid disturbance in the functioning .of the alternator.

As shown in Fig. 1, the battery S thatwas used for the heating of the filament could be eliminated. The filament F could be fed by alternating current and it will be suflicient if a small adjustable transformer H is provided. The primary of this transformer is fed bythe alternator and the secondary feeds the filament. The alternator may be provided with a special low potential winding. The alternator may be diphased, one phase serving for the heating of the filament and the other for the feeding of the plate filament circuit.

Fig. 3 represents a second embodiment of the invention in which two cathodic generators are connected as a rectifier whereby the two alternations of the alternating current will be utilized. In this circuit, the terminals of the alternator are shunted by an auto-transformer E having a middle point 0 and the two generators L and L" res ctively, are connected between the mi dle point and the ends of the auto-transformer. This connection is so arranged that one generator permits the passage of the upper and the other generator permits the passage of the lower alternations.

Fig. 4 shows a curve representin the intensity of the continuous waves in t e transmitting antenna.

Due to the variations in the intensity of the continuous waves, these may be received by means of a usual receiver, e. g. by a simple crystal detector. In this case, the tone corresponds to double the frequency of the alternator.

It should be noted that the potential curve of the alternator could be chosen in a manner to give the best receiving efiiciency. In the case of Fig. 2, a rectangular curve would be preferable. In the case of Fig. 4., the best would be a rectangular curve extending over of the period.

Instead of utilizing two tubes in Fig. 3, four tubes may be used as in the well known rectifier circuit arrangements.

The alternator may be constructed without sliding contact by providing a stationary armature and a movable field. The field may comprise a permanent magnet or the excitation may be accomplished by a condenser provided in the armature circuit. If storage batteries are used for maintaining the heating of the filament, they may be used also for energizing a homopolar alternator provided with rotating armature.

If an inside permanent magnet is used in the field, the use of sliding contacts may be avoided by means of twin machines connected in cascade.

The heating by alternating current will have the advantage of being effected at a potential as low as 1 volt, whereby thick and strong filaments may be used. If the alternator is driven at a variable speed, the heating of the filament will be none the less constant if the inductance of the alternator is relatively high with respect to the external resistance.

The cathodic generator provided in the arrangement previously described, instead of being a self energizing generator as described, may be a generator with separate energization, i. e. a generator in which theplate-filament circuit and the grid-filan'ient circuit are separate. The rid filament circuit of the generator will e supplied with current by a small auxiliary generator, which may again be a cathodic auto-energizing (self-exciting) generator. This arrangement would have the advantage that the continuous waves sent out by the antenna will be started immediately and that the system would not have a more or less uncertain starting period.

The sending station can be as well distin'guished by the alternating current as by the wave-length.

Obviously, a continuous potential of a suitable relative value may be superposed on the alternating potential applied. to the plate filament circuit, for the urpose of avoiding a complete stoppage o the transmission. Such method of functioning may be accomplished e. g. by using a direct ourrent dynamo the potential of which is subject to great fluctuations. By means of two collector rings, this dynamo may serve also for supplying the alternating current for low potential heating.

The potential fluctuations of the dynamo in questionbould be reinforced to a higher degree by providing a capacity of suitable value at'its terminals.

Instead of a collector rectifier, cathodic rectifiers may be used in combination with well known circuits (mercury rectificrs, lie notrons, etc.)

In accordance with the modification of Fig. 5, the capacity C shunting the alternator in Fig. 1 instead of being made sufficiently Weak to prevent disturbance in the functioning of the alternator, may on the contrary be of suitable value to produce an over-excitation and even self-excitation of the alternator. In this manner, the inductor winding and the eXciter may be eliminated and this is of great advantage when it is desired to produce a strong machine having a weak power.

In the arrangement described in which the transmitting station may be distinguished as Well by the tone of the alternating current as by .the wave length. it should be noted at this point that, by means of a simple switch, the circuit arrangement schematically illustrated in Fig. 3 makes possible the obtaining of two tones, one of these tones being the octave of the other. Fig. 5 shows the details of such arrangement. Two lamps L are connected, respectively, between the middle point 0 and the ends of the auto-transformer E, the arrangement being such that one of the tubes permits the passage of positive alternations and the other tube permits the passage of negative alternations (obviously, instead of the auto-transformer, the alternator I) may be provided with two separate windings having a common point).

The operation of the cireuitwill be ob vious from the previous description, the same reference characters designating the same elements.

In order to obtain a tone the tonality of which is equal to the frequency of the alternator, it is sufiicient if by means of a switch K we reverse the connections of one of the windings of the auto-transformer E with the corresponding tube.

In this case, the two tubes will operate in 7 parallel. v In case it is desired to obtain other tones,

it is always possible to provide the alternator D with windings to change the number of poles in the well known manner.

The doubling of the number of poles may be easily accomplished if monophase windings are used.

.ity of stations close to one another.

By combining this arrangement with the above disclosed invention, in response to the operation of the switch, three distinct tones may he obtained at will, e. 300, 600, 1200. V

The possibility of changing the tone of the sending is of great importance if it is desired simultaneously to operate a plural- It should be notedthatthe circuits of the two tubes must be perfectly synnnetrical with respect to each other, in order that the waves separately produced by each tube have exactly the same value and that there by the full benefit of continuous waves be derived.

The present invention may also be applied to wireless telephony using the apparatus and circuits described.

I This is based on the following experimental observation. 'llf in an ordinary microphone the usually employed current source is substituted by an alternating current source, the microphone may always function for the transmission of the conversation and the only inconveniencewill be that we will hear in the receiver a musical sound having a tone corresponding to the frequency of the alternating current. This tone does not appreciably interfere with the audibility of the conversation and this is particularly true if the tone corresponds to a frequency inferior to one hundred periods or superior to 2000 periods.

Above this last mentioned frequency, the receiving is always satisfactory, it the alternating current enters the microphone intermittently.

Let us consider in view of this the cathodic generator system shown in Fig. 6 which is similar to Fig. 3. It comprises two cathodic generators Lhaving a common oscillating cAirpZuit H C and a coupled antenna circuit The generators are fed by an alternating current source through an auto-transformer E. Such system sends out continuous waves of variable intensity, whereby a tone will be produced in the receiving circuit. The

sending of these waves is utilized for obtaining direct receiving in wireless telegraphy, without heterodyne or ticker.

Tn view of the above outlined experimental observation, the system may be used for wireless telephony in all cases and under the same conditions as though the system were fed by a constant direct current potential. As above stated, the tone will interfere the less with the clearness of the conversation, the lower it is below 100 periods or the higher it is above 9000. lit is sutlicient therefore, if the microphone illustrated at M in Fig. 6 is added to the circuit in shunt to the inductance in the antenna circuit.

Obviously, the microphone could be proof which have a common point connected to 7 the neutral point of the alternator through the oscillating circuit H C.

It will be seen that, when applied to wireless telephony, the sound heard in the receiver permits the recognition of the sending station and we may make sure of its functioning even if no microphone is used.

Obviously, all types of machines and circuits previously described apply equally well in the application to wireless telephony.

An arrangement may also be provided whereby the same technical effect may be obtained as with an alternating current generator with a direct current source of suffi- 'ciently high potential.

In accordance with this modification, the high frequency circuits of the usual vacuum tube generator are combined with a new low frequency oscillating circuit, or sound circuit. As a result of the reactions caused by the new oscillations circuit, the electro-magnetic waves sent by the antenna A. are no more of a constant am litude, but this amplitude varies regular y and continuously with the time. result is obtained as in the case of alternating current supply.

Qne possible circuit arrangement 0 5111- prises an auxiliary condenser connected in series with the plate source S, and its terminals are shunted by a self inductance of suitable value and inductively connected with the grid circuit G lln this case the oscillating circuit tormed by the condenser and auxiliary inductance will have an individual oscillation period corresponding to the tone we desire to ob tain in the telephone receiver.

The individual capacity of the inductance windings may be sufficient for replacing the auxiliary condenser.

Another method consists in providing this auxiliary condenser (in series with an inductance or otherwise) as a shunt between the grid G and the filament ll.

lln this case, the frequency of this oscillating circuitinay be regulated with respect to the frequency of the main oscillating circuit comprising the condenser C in such a manner that beats will be produced and will cause the periodic variation of the amplitude of the waves sent by the antenna.

Other circuits may be readily arranged,

As a result of this, the same all being characterized by the addition of a new oscillating circuit for the above mentioned purpose. 1

Having described my invention, what I claim is:

1. In a radio signaling system, the combination of two vacuum tubes each having an anode and a cathode, an alternating current source having a tone frequency, a coil connected in shunt to the terminals of the alternating current source and a connection from amid point of said coil to said cathodes, said plates being connected to said coil at opposite sides of said mid point.

2. In a radio signaling system, the combination of two vacuum tubes each having an anode and a cathode, an alternating current source of tone frequency, a coil having two points connected to the anodes and a common point connected to the cathodes, means for reversing one part of the coil with respect to the other and an alternating current source of tone frequency connected to said coil. I

3. In a radio signaling system, the combination of two vacuum tubes, each having an anode, a cathode and a grid, a coil conuectiug said anodes, a conductor connecting said grids, a tuned circuit common to the anode-cathode circuits of the two tubes, a connection from a mid point of said coil to said tuned circuit, a source of current of tone frequency beyond the range of ordinary speech frequencies connected to said coil, a circuit connected to the filament and to the grid connection, a coil in said circuit coupled to the tuned circuit, and an antenna circuit coupled to one of the valve circuits.

4. Thermionic oscillation-producing means comprising a plurality of anode circuits provided with control electrode and cathode structure, inductance common to said anode circuits, a common coupling between said anode circuits and said control electrode structure, a source of fluctuating current having its terminals connected to the anodes of said anode circuits, and a connection from a point intermediate the terminals of said source connected through said inductance to said cathode structure.

5. The method of transmitting intelligence by radio frequency energy, which consists in subjecting a pair of thermionic oscillation-producing paths to low frequency fluctuating signal-representing voltage, selecting in the different paths and converting into sustained oscillations therein the positive and negative current waves produced by said signal-representing voltage, producing electron emission for said oscillation-producing paths by fluctuating current in synchronisni with said signal-representing voltage, and alternately impressing upon a transmitting medium the different groups of oscillations.

meme? 6. Thermionie oscillation-producing means comprising a plurality of anode circuits provided with cathode and control electrode structure, means common to said anode circuits for coupling them with said control electrode structure to produce oscillations, condensers connected respectively, in said anode circuits, and a source of fluctuating voltage connected in shunt with each of said condensers.

7 'lhermionic means for producing oscillations from both positive and negative waves of a source of fluctuating current, means comprising a pair of anode circuits normally without oscillation producing energy, and control electrode structure coacting therewith to produce oscillations, of a transformer secondary in each of said anode circuits, a condenser in shunt with each of said transformer secondaries, and coacting in the production of said oscillations, and a source of fluctuating current for producing in each of said-secondaries fluctuating voltage,

8. 'lherinionic oscillation producin means comprising the combination with a p urality of thermionic anode circuits, of means for supplying electrons thereto, control electrode structure coupled to said anode circuits, condensers in series with each other connected to the anodes in said anode circuits, transformer secondaries shunting said condensers, and a connection from a point between said condensers to said electron supplying means.

9. Thermionic oscillation-producing means comprising a pair of anode circuits each provided with control electrode and cathode structure, means coupling said control electrode structure with said anode circuits to produce oscillations, of a transformer secondary having its terminals connected, respectively, to the anodes of said circuits, a connection from the middle of said secondary to said cathode structure, a primary winding, a source of fluctuatin current in circuit with said primary winding, and a condenser for each anode circuit coacting in producing oscillations and connected to the anode thereof and to said cathode structure.

10. Thermionic oscillation producing means comprising a pair of anode circuits normally without oscillation l producing energy and provided with controlelectrode and cathode structure a common couplin between said control electrode structure and said anode circuits, a condenser connected in series with each anode circuit, and synchronous sources of fluctuating current connected, respectively, in shunt to said condensers.

11. Thermionic oscillation producing means comprising a plurality of anode circuits provided with control electrode and cathode structure, inductance common to said anode'circuits, a common coupling between said inductance and said. control electrode structure, a transformer secondary having its terminals connected to the anodes of said anode circuits, a source of signaling current in the transformer primary circuit. and a connection from the middle of said transformer secondary to said cathode structure.

12. Thermionic oscillation producing means comprising a plurality of anode circuits provided with control electrode and cathode structure, inductance common to said anode circuits, a common coupling between said inductance and said control electrode structure, a transformer secondary having its terminals connected to the anodes of said anode circuits, a source of signaling current in the transformer rimary circuit, a connection from the midd e of said transformer secondary'to said cathodestructure,

from a point between said con and a condenser in shunt to each part of said secondary. V

13. Thermionic oscillation producing means comprising a plurality of anode circuits provided with control electrode and cathode structure, inductance common to said anode circuits, a common coupling between said anode circuits and said control electrode structure, a source of fluctuating from a point intermediate the terminals of said source connected through said inductance to saidcathode structure, condensers connected in series with each other across the terminals of saidsource, and a connection densers to said cathode structure.

14. Thermionic oscillation producing means comprising a pluralit of anode circuits provided with catho e and control electrode structure, means common to said anode circuits for coupling them with said control electrode structure to produce oscillations, condensersrconnected in series with each other across the anodes of said circuits, a connection from a point between said condensers to said cathode structure, windings having terminals connected to a point between said condensers and having their other terminals connectedto the other terminals of said condensers, and means for producmg between said other terminals of said zvirlidings a fluctuating difierence of poten- 15. Thermionic oscillation producing means comprising a pluralit of anode .circuits, provided with catho. e and control electrode structure, means, common to said anode circuits for coupling them with said control electrode structure to produce oscillations, condensers connected in series with each other across the anodes of said circuits, a connection from a point between said condensers to said cathode structure, transformer structure having secondaries connected, respectively, in shunt to said condensers, andsa source of fluctuating current in the primary circuit of said transformer structure.

16. Thermionic oscillation producing means comprising a plurality of anode circuits provided with cathode and control electrode structure, means common to said anode circuits for coupling them with said control electrode structure to produce oscillations, comprising condensers connected in series with each other across the anodes of said circuits, a connection from a point between said condensers to said cathode structure, a source of fluctuating current for heating said cathode structure, and windings energized by said source of current and connected, respectively, in shunt to said condensers.

17. Thermionic' oscillation producing means comprising the combination with a pluralit means or supplying electrons thereto, control electrode structure coupled to said anode circuits for producing oscillations, condensers in series with each other connected to the anodes in said anode circuits, a connection from a point between said condensers to said electron-supplying means and a source of oscillation-producing energy connected in shunt with each of said condensers.

18. Oscillation-producing means comprising the combination with a plurality of thermionic anode circuits, of means for supplying electrons thereto, control electrode structure, means common to said anode circuits for coupling them with said control electrode structure for producing oscillations, a condenser in series with each anode circuit, and a source of fluctuating oscillation-producing current connected in each anode circuit in a path in parallel with the condenser therein.

19. Oscillation-producing means compris ing the combination with a pair of thermionic anode circuits, of means for supplying electrons thereto, control electrode struc ture coupled to said anode circuits for 'producing oscillations, condensers connected in series with each other to the anodes of said anode circuits, a source of alternating current, and means connected in paths in paral-.

lel, respectively, with said condensers and delivering energy of positive and negative waves of said source to said anode circuits,

respectively.

MARIUs rarroun.

of thermionic anode circuits, of 

